The present invention relates to a high quality factor, integrated inductor and a production method thereof.
As is known, inductors are key components of the operating blocks of a radio-frequency circuit. Their critical parameters comprise the inductance value L, the quality factor Q, and the resonance frequency f. Many applications, such as GSM cellular communications systems, require inductors which have inductance L of 1-10 nH, a quality factor Q of at least 10, and a resonance frequency which is far greater than 1 GHz.
Integrated inductors made of aluminum, which have a quality factor Q of 3, can easily be produced by means of standard microelectronics processes. The quality factor Q is however limited by the parasitic capacitance towards the substrate, and by the resistance of the inductor itself. Consequently, it is not possible at present to produce integrated inductors of semiconductor material which have a high quality factor. For applications which have high requirements, discrete inductors external to the integrated silicon device are used.
An object of the invention is thus to provide an inductor which has a high quality factor.
The present invention provides a high quality factor integrated inductor and production method thereof. In one embodiment of the present invention, the integrated inductor comprises a coil of conductive material wherein said coil is supported by a bracket extending above and spaced from a semiconductor material body by an air gap. The bracket is carried by the semiconductor material body through support regions.
To enable the present invention to be understood, a preferred embodiment is now described, purely by way of non-limiting example, with reference to the attached drawings.